The flap copy on this collection of lesser-known Mother Goose poems notes that nursery rhymes often deal with disturbing subjects, yet their reassuring nonsense puts ``trouble into proper perspective.'' Readers may nevertheless question the reason for collecting 18 verses that are decidedly less upbeat than most. Each deals with ill luck of one sort or another, ranging from Miss Mackay's loss of her knives and forks, to the demise of a handsomely dressed soldier who ``had a fight, / He died of fright, / And that was the end of Corporal Tim.'' In his eloquent introduction, Marcus emphasizes the importance of playful rhythm and rhyme to the overall effect of these verses, remarking that they should not be read for their content only. Yet a number of these poems lack the buoyance and zip of the more familiar Mother Goose rhymes, and sound curiously flat when read aloud. Despite Schwartz's characteristically humorous illustrations, this is a somewhat uninspired collection. All ages. (Aug.)